An OBD reader will not change the Pace Car Indicators, you need Carly, OBDEleven or a VCDS cable (or know someone local that has one) and also need it long coding out and not the App as you do not know how it has been done.
Having never seen or used any of what you've just mentioned it's like a whole new language to me, i have heard them mentioned but stupidly thought it was just a case of plugging in said device and looking at indicator options
I think you can also buy a plug in adaptor that does it too. Might be worth having a quick look at the back of the light units to see if something has obviously been added.
I'll have a rummage around and see if i can see anything the looks out of the ordinary.
I've just watched a couple of videos where people have done it on OBDEleven and VCDS, i don't know the cost of either of them but i don't see the point in me buying something that i'll only use once as i have no desire to tinker around with the software. I'm more pissed at VW for blatantly selling me a car that had an MOT advisory for a software modification that they should be able to quickly rectify, so i will be paying them a visit!